Canon imageRUNNER ADVANCE C256i Drum Unit Bk

This drum unit series places particularly high demands on the quality and durability of the drum core. One of the key factors is the **thickness and quality of the OPC coating**. An original drum core typically has an OPC coating thickness of approximately 42 nanometers, while many compatible drum cores available on the market use coatings of less than 30 nanometers. A thinner OPC coating may be more susceptible to **electrostatic breakdown**, particularly during long-term or high-volume printing. In actual use, this problem may initially appear as **small, evenly distributed black dots** on the printed page. As the drum core continues to deteriorate, these dots can develop into a continuous black line or repeated line defect. Once electrostatic breakdown has occurred, replacing other components of the drum unit may not resolve the problem. In most cases, the drum core itself needs to be replaced with a higher-quality one. ### How Does Hotsun Address This Issue? For our IRC256 / GPR58 / C-EXV55 / NPG76 compatible drum units, we use **high-quality, long-life Fuji OPC drum cores** with an OPC coating thickness of approximately 40 nanometers. The thicker and more durable OPC coating provides improved resistance to electrostatic breakdown and helps maintain stable print quality throughout the service life of the drum unit. **If you are experiencing black lines or repeated black dots with an IRC256 / GPR58 / C-EXV55 / NPG76 drum unit, the drum core quality is one of the key factors worth checking.**